Clinical manifestation

Nail changes: absent or short nail plate; V-shaped triangular lunulae with a distal peak in the midline; other abnormalities include: splitting, longitudinal ridging, koilonychia, poor lunula formation, and discoloration Skeletal changes: small or absent patella; elbows may have limited motion; subluxation of the radial head; arthrodysplasia of the elbows; hyperextension of the joints; exostoses

Kidney changes: usually only asymptomatic proteinuria, but hematuria, neph-rotic syndrome, and renal failure may occur